how to give Edittext and button to half of the screen width?

below is my login screen.I need to give both EditText and Button to take half of the screen width.can we archive this using weight ?unless i have to give margin values specifically for each type of screens(small,large,...)?

Weights only work with LinearLayout. For a perfect 50/50 split in a RelativeLayout you can put a view centered in the layout, then put your views to the left and right of the strut. Something like this:

You can adjust the spacing more or less than 50/50 by putting a left margin on the space. Example: